Characteristics of patients admitted to the emergency department due to tick bite

Abstract

Crimean-Congo haemorrhagic fever (CCHF) is a tick-borne disease endemic in Turkey since 2002. Çorum is one of the leading five cities in Turkey in which CCHF disease is seen most. We studied characteristics of the patients with tick bites in our emergency department (ED) and determined the fatality rate of the disease in city of Çorum for the first time. We retrospectively analysed the characteristics of the patients admitted to our ED from the medical files of 21,680 patients in a 5-year period. The number of patients with definite diagnosis and who have died was determined. Our results demonstrated that the fatality rate of CCHF in Çorum is 6.78%. Among 21,680 patients, blood samples of 970 patients were sent to an advanced centre in Ankara for polymerase chain reaction (PCR) testing. Results of 560 patients were reported to be PCR (+) and 38 of them have died.

Keywords

Crimean-Congo haemorrhagic fever fatality rate emergency department

Introduction

In Turkey, especially since 2002, Crimean-Congo haemorrhagic fever (CCHF) has been a serious public health problem threatening lives of thousands of people. A regional epidemic has occurred in Turkey in 2003 and since then, when considering the number of CCHF cases reported worldwide, the highest number has been reported in Turkey. The majority of cases in our country were from 15 cities in a region called Kelkit Canyon and its environs in the middle and North Anatolia, particularly the cities of Çorum, Tokat, Sivas, Yozgat and Erzurum from which two-thirds of cases were reported.^1,2 In this article, we aimed to reveal the characteristics of the patients admitted to our emergency department (ED) due to tick bite and reveal the characteristics of the patients under risk. We also determined the fatality rate of CCHF in a 5-year period.

Material and methods

We retrospectively collected the medical data of 21,608 patients admitted to Hitit University Çorum Education and Research Hospital ED between 2008 and 2012. From the medical records of the patients, demographical features and laboratory findings were recorded on a SPSS (Statistical Package for Social Science) 20.0 programme. We also collected the medical data of patients whose blood samples were sent to an advanced centre in Ankara for detection of viral RNA by reverse transcriptase-polymerase chain reaction (RT-PCR) measurements in order to make a definite diagnosis of CCHF. Descriptive statistical analysis was performed for demographical variables. Chi-square test was used to determine and compare fatality rates in a 5-year period.

Results

When the demographical properties of 21,608 patients were evaluated, we found that 60.2% of the patients were male and 2011 was the year most of the patients were admitted due to tick bite (35.4%). It was observed that majority of the cases were admitted in the summertime, particularly in June and July (47.4%). Most of the patients were located in the city centre (89.7%). With a proportion of 22.2%, children were the most affected group. See Table 1 for the basic characteristics of the patients.

Table 1.

Demographical characteristics of the patients admitted to ED due to tick bite.

Sex	n	%	Month	n	%
Male	12999	60.2	January	28	01
Female	8609	39.8	February	52	02
Age (Interval)	n	%	March	293	14
0–18	4799	22.2	April	1657	77
19–28	2615	12.1	May	3661	16.9
29–38	3007	13.9	June	5349	24.8
39–48	3155	14.6	July	4875	22.6
49–58	3509	16.2	August	2545	11.8
59 and over	4523	20.9	September	1603	7.4
Year	n	%	October	1069	4.9
2012	7650	35.4	November	417	1,9
2011	3620	16.8	December	59	0.3
2010	4159	19.2	Location	n	%
2009	3419	15.8	City center	19376	89.7
2008	2760	12.8	Rural areas	2232	10.3

After the first visit, patients were recalled to the hospital three times for control blood tests. It was observed that the number of following visits of the patients tended to decrease. When laboratory findings were investigated, it was observed that mean values of WBC, haemoglobin, PLT, AST and ALT values on admission, at the fourth and eighth days were in normal limits.

In the 5-year period the mean fatality rate of CCHF in Çorum city was found to be 6.78%. The number of patients who died due to CCHF was not found to be significantly different according to years (Chi-square 0.6842, P = 0.953). Results of the PCR tests and the number of the patients who died according to year are summarised in Table 2.

Table 2.

PCR results of the patients according to years.

Year	2008	2009	2010	2011	2012
Number of blood samples sent to Ankara	198	206	151	245	170
PCR (+)	122	134	88	137	79
Death	9	8	7	8	6

Discussion

CCHF virus causes a fatal haemorrhagic syndrome, which has been endemic in the central, northern and eastern regions of Turkey in recent years.¹

More patients are seen in the summer months, i.e. April to September, with a peak incidence in June and July. The climate of this middle Anatolian region is hot, dry summers with cold and moderately rainy winters, which are the optimum conditions for survival of the Hyalomma tick population.^2,3 In our study, compatible with the literature, we determined that most of the patients with tick bite were admitted to our ED in summer seasons, particularly in June and July.

In a study, it was reported that the disease is common in the rural areas of the region and in the actively working age group. Nearly two-thirds of the patients in that study were farmers and homemakers in the rural areas.² Contrary to what we know, in our study, it was observed that majority of the patients were living in the city centre. This may be due to good follow-up with repeated blood tests performed by the experienced physicians in the rural areas.

It is known that almost all of the patients with CCHF disease have leukopenia, thrombocytopenia, and elevated AST, ALT, LDH and CPK levels.¹ In a study from Turkey, higher AST and ALT levels were found to have higher sensitivity for severe cases.⁴ In our study, when all patients with tick bite were considered, it was determined that the mean blood test results were found to be in normal limits.

The gradual increase in the number of cases over the latter 2 years may have been associated with regional dispersion of the disease as well as increased awareness of healthcare personnel and the public about the disease.^2,5 In our study, while the number of deaths due to CCHF was not found to be significantly different according to years, it was determined that in 2008, 2010 and 2012, more patients died than in years 2009 and 2011.

We determined that deaths due to CCHF tended to decrease while the fatality rate increased. While the number of patients with a definite diagnosis of CCHF decreased, due to problems with the treatment, there was not an adequate decrease in fatality rates.

The reported mortality rate of CCHF is in the range of approximately 5–70%.⁶

The mean fatality rate for Turkey is about 5%. The lower fatality rate in Turkey compared to the rates reported by other countries may be due to a better surveillance system, which facilitates the detection of cases with mild to moderate clinical findings, and relatively better treatment facilities.²

Our study revealed that a significant decrease in fatality rates could not have been obtained over the years. We also determined that the fatality rate of CCHF in Çorum was 6.78% in the 5-year period.

Conclusion

Our results revealed that this disease is not a threat only for people living in rural areas but also city dwellers. The mean fatality rate of CCHF patients in Çorum is 6.7%. Over the years, the fatality rate of CCHF could not have been reduced. The disease is still a major public health problem that physicians in Turkey should be aware of.

Footnotes

Declaration of conflicting interests

None declared.

Funding

This research received no specific grant from any funding agency in the public, commercial or not-for-profit sectors.

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